Disgraced cyclist Lance Armstrong has admitted he took performance-enhancing drugs and used blood transfusions as he won his seven Tour de France titles.

In an interview with Oprah Winfrey, the 41-year-old said it was "not possible" to win the the gruelling race so many times without doping.

Armstrong confessed that he doped during all seven Tour victories from 1999 to 2005, using blood-boosting agent EPO; blood doping; testosterone, cortisone or human growth hormone.

"My cocktail was EPO, transfusions and testosterone," he said.

"I made my decisions. They're my mistake. And I'm sitting here today to acknowledge that and to say I'm sorry for that,"

The Texan, who won the world road race title in 1993, added that his drug use began in the "mid-90s".

"I suppose earlier in my career there was cortisone and then the EPO generation began," he said.

However, he said at the time he did not believe what he was doing was cheating.

"I looked up the definition of cheat. The definition of cheat is to gain an advantage over a rival or foe," Armstrong said. "I didn't do that. I viewed it as a level playing field."

Armstrong, who has already had his Tour wins taken away and been banned from the sport for life, acknowledged his admission was probably "too late" for most people.

"I view this situation as one big lie, that I repeated a lot of times. It wasn't as if I just said no."

He had repeatedly previously denied all accusations made against him, despite the United States Anti-Doping Agency found him to be a central figure in "the most sophisticated, professionalised and successful doping programme that sport has ever seen".

Although Armstrong acknowledged the doping, he rejected some of USADA's claims about his US Postal team, saying: "It was definitely professional and it was definitely smart, if you can call it that. But it was very conservative, very risk averse."

"But to say that that programme was bigger than the East German programme in the mid-80s, it's not true."

Although he denied forcing others on the team to take banned substances, he said he led by example and admitted being a "bully".

Armstrong was adamant he did not dope or perform blood transfusions in 2009 or 2010, when he made his comeback to the sport, saying: "The last time I crossed that line was 2005."

He said that allegations he did take banned substances during this comeback period were the only thing in the USADA's detailed report that "really upset" him.

It was out-of-competition testing and the so-called biological passport, which collates biological markers of doping and doping tests, that forced him to stop.

The interview was recorded in Armstrong's hometown of Austin, Texas, three days before it was broadcast.